The class of polymers of carbon monoxide and olefin(s) has been known in the art for some time. Brubaker, U.S. Pat. No. 2,495,286, produced such polymers of relatively low carbon monoxide content in the presence of free radical initiators, e.g., peroxy compounds. U.K. No. 1,081,304 produces similar polymers of higher carbon monoxide content in the presence of alkylphosphine complexes of palladium as catalyst. Nozaki extended the reaction to produce linear alternating polymers in the presence of arylphosphine complexes of palladium moieties and certain inert solvents. See, for example, U.S. Pat. No. 3,694,412.
More recently the class of linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon has become of greater interest, in part because of the greater availability of the polymers. More recent processes for the production of these polymers, also known as polyketones or polyketone polymers, is illustrated by a number of published European Patent applications including Nos. 121,965, 181,014, 213,671 and 257,633. The process, now broadly considered conventional, generally involves the use of a catalyst composition formed from a Group VIII metal selected from palladium, cobalt or nickel, the anion of a non-hydrohalogenic acid having a pKa below about 6, preferably below 2, and a bidentate ligand of phosphorus, arsenic or antimony.
The resulting polymers are relatively high molecular weight materials having utility as premium thermoplastics in the produciion of shaped articles by methods conventional for the processing of thermoplastics. Although the polymers are relatively stable, the linear alternating polymers do undergo to some degree the degradation by exposure to elevated temperatures and to ultraviolet light characteristic of most if not all organic polymers.
Russell et al, U.S. Pat. No. 3,929,729 and U.S. Pat. No. 4,024,104, teach the use of certain benzophenones and of certain benzotriazoles as thermal stabilizers of certain polymers of carbon monoxide and ethylene with the optional presence of third monomers. Although the disclosure of the scope of polymers by Russell et al is rather broad, the scope of polymers tested is rather narrow and the Russell et al teachings do not appear to be particularly directed toward linear alternating polymers. In copending U.S. patent application Ser. No. 167,801, filed Mar. 14, 1988 (Docket No. K-0730) there is disclosed a class of stabilizers useful to retard the degradation by UV light of the linear alternating polymers of carbon monoxide and at least one ethylenically unsaturated hydrocarbon. Among the members of this class are diphenylamines of defined structure, including 4,4'-bis(.alpha.,.alpha.-dimethylbenzyl)diphenyl amine, a commercial antioidant marketed by Uniroyal as NAUGARD.RTM. 445 Antioxidant. Although the use of this and related diphenylamines is useful in retarding degradation caused by exposure to UV light, it would be of advantage to provide improved UV stabilization.